Recyclability of thermosetting polymers and their composites is a challenge for alleviating environmental pollution and resource waste. In this study, solvent-recyclable thermosetting polyimide (PI) and its composite were successfully synthesized. The tensile strength, elongation at break, and Young’s modulus of PI are 108.70 ± 7.29 MPa, 19.35% ± 3.89%, and 2336.42 ± 128.00 MPa, respectively. The addition of reduced graphene oxide (RGO) not only enhances the mechanical properties of PI but also endows it with excellent tribological properties. The PI illustrates a high recycling efficiency of 94.15%, but the recycled composite exhibits inferior mechanical properties. The recycling and utilization of PI and its composite are realized through imine bonds (–C=N), which provides new guidance for solving the problem of environmental pollution and resource waste and is potential application in the field of sustainable tribology.

Two-dimensional (2D) lamellar materials have unique molecular structures and mechanical properties, among which molybdenum disulfide (MoS₂) and graphitic carbon nitride (g-C₃N₄) with different interaction forces served as reinforcing phase for polytetrafluoroethylene (PTFE) composites in the present study. Thermal stability, tribological and thermomechanical properties of composites were comprehensively investigated. It was demonstrated that g-C₃N₄ improved elastic deformation resistance and thermal degradation characteristics. The addition of g-C₃N₄ significantly enhanced anti-wear performance under different loads and speeds. The results indicated that PTFE composites reinforced by g-C₃N₄ were provided with better properties because the bonding strength of g-C₃N₄ derived from hydrogen bonds (H-bonds) was stronger than that of MoS₂ with van der Waals force. Consequently, g-C₃N₄ exhibited better thermomechanical and tribological properties. The result of this work is expected to provide a new kind of functional filler for enhancing the tribological properties of polymer composites.